Bradykinin and Neurotensin Analogues as Potential Compounds in Colon Cancer Therapy.

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide, so the attempts to find novel therapeutic approaches are necessary. The aim of our study was to analyze how chemical modifications influence physical, chemical, and biological properties of the two peptides, namely, bradykinin (BK) and neurotensin (NT). For this purpose, we used fourteen modified peptides, and their anti-cancers features were analyzed on the HCT116 CRC cell line. Our results confirmed that the spherical mode of a CRC cell line culture better reflects the natural tumour microenvironment. We observed that the size of the colonospheres was markedly reduced following treatment with some BK and NT analogues. The proportion of CD133+ cancer stem cells (CSCs) in colonospheres decreased following incubation with the aforementioned peptides. In our research, we found two groups of these peptides. The first group influenced all the analyzed cellular features, while the second seemed to include the most promising peptides that lowered the count of CD133+ CSCs with parallel substantial reduction in CRC cells viability. These analogues need further analysis to uncover their overall anti-cancer potential.

Biological and Physico-Chemical Characteristics of Arginine-Rich Peptide Gemini Surfactants with Lysine and Cystine Spacers.

Ultrashort cationic lipopeptides (USCLs) and gemini cationic surfactants are classes of potent antimicrobials. Our recent study has shown that the branching and shortening of the fatty acids chains with the simultaneous addition of a hydrophobic N-terminal amino acid in USCLs result in compounds with enhanced selectivity. Here, this approach was introduced into arginine-rich gemini cationic surfactants. l-cystine diamide and l-lysine amide linkers were used as spacers. Antimicrobial activity against planktonic and biofilm cultures of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) strains and Candida sp. as well as hemolytic and cytotoxic activities were examined. Moreover, antimicrobial activity in the presence of human serum and the ability to form micelles were evaluated. Membrane permeabilization study, serum stability assay, and molecular dynamics were performed. Generally, critical aggregation concentration was linearly correlated with hydrophobicity. Gemini surfactants were more active than the parent USCLs, and they turned out to be selective antimicrobial agents with relatively low hemolytic and cytotoxic activities. Geminis with the l-cystine diamide spacer seem to be less cytotoxic than their l-lysine amide counterparts, but they exhibited lower antibiofilm and antimicrobial activities in serum. In some cases, geminis with branched fatty acid chains and N-terminal hydrophobic amino acid resides exhibited enhanced selectivity to pathogens over human cells.

Triiodothyronine lowers the potential of colorectal cancer stem cells in vitro.

Cancer stem cells (CSCs) play a key role in the development and progression of colorectal cancer (CRC), but the influence of triiodothyronine (T3) on the biological regulation of CSCs remains unclear. In the present study, it was reported that T3 exerts significant impact on CSCs of two CRC cell lines cultured in the form of colonospheres. It was observed that the incubation of colonospheres with T3 decreased the viability, proliferative and spherogenic potential of cancer cells (P<0.05). In addition, increased apoptotic rate of CRC cells treated with T3 was revealed. Furthermore, T3­treated colonospheres were more likely to move into silenced pool in G0/G1 phase of the cell cycle. The smaller sizes of colonospheres observed after the treatment with T3 confirmed this conclusion. T3 could lower the proportion of primitive cells which supply the pool of proliferating cells within spheres. Thyroid receptors THRα1 and THRß1 and two deiodinases (DIO2 and DIO3) were affected by T3 in manner depended on clinical stage of cancer and CRC cell line used for analysis. In summary, the present study uncovered a novel function of thyroid hormones signaling in the regulation of the CSCs of CRC, and these findings may be useful for developing novel therapies by targeting thyroid hormone functions in CRC cells.

Effects of 5-FU and anti-EGFR antibody in combination with ASA on the spherical culture system of HCT116 and HT29 colorectal cancer cell lines.

The aim of this study was to examine the effects of 5­fluorouracil (5­FU), anti­epidermal growth factor receptor (EGFR) antibody and aspirin (ASA) on the characteristics of two CRC cell lines, HCT116 and HT29, maintained in a spherical culture system. We observed that the morphology of both the HCT116 and HT29 cell­derived spheres was significantly impaired and the size of the colonospheres was markedly reduced following treatment with the aforementioned three drugs. In contrast to adherent cultures, the spherical cultures were more resistant to the tested drugs, as was reflected by their capacity to re­create the colonospheres when sustained in serum­free medium. Flow cytometric analysis of the drug­treated HCT116 cell­derived spheres revealed changes in the fraction of cells expressing markers of cancer stem cells (CSCs), whereas the CSC phenotype of HT29 cell­derived colonospheres was affected to a lesser extent. All reagents enhanced the percentage of non­viable cells in the colonospheres despite the diminished fraction of active caspase­3­positive cells following treatment of the HT29 cell­derived spheres with anti­EGFR antibody. Increased autophagy, assessed by acridine orange staining, was noted following the incubation of the HT29­colonospheres with ASA and 5­FU in comparison to the control. Notably, the percentage of cyclooxygenase (COX)­2­positive cells was not affected by ASA, although its activity was markedly elevated in the colonospheres incubated with anti­EGFR antibody. On the whole, the findings of this study indicate that all the tested drugs were involved in different cellular processes, which suggests that they should be considered for the combined therapeutic treatment of CRC, particularly for targeting the population of CSC­like cells. Thus, cancer cell­derived spheres may be used as a preferable model for in vitro anticancer drug testing.